Switching order of links

Links should be able to be sorted ascending or descending.

A default need to be chosen. I propose to have a visual indication (color, arrow...) to know which sorting we are on. When clicking again on the sorting button, the mode (ascending/descending) and the visual indication should be updated

No files or tests are named. Start by locating the link list and its current sorting control, then trace how the selected order is stored and displayed; done means repeated clicks switch ascending and descending order and provide a visible indication of the active mode.

Written by the indexing model from the issue text.